The invention pertains to the commutation process employed in electrical machines, such as DC machines (motors and generators), AC commutator machines (series motors, repulsion motors, commutator-type induction motors of the Schrage design and others), DC to AC and DC to DC converters, etc. A commutator with its brushes serves the function of substituting the electrical coils of an armature during the relative motion (rotation) of the armature and a field, by establishing and disestablishing contact, through commutator segments and brushes, between successive coils and an external circuit, which is either a source of electrical energy (in case of a motor) or a receptor of same (in case of a generator).
The present invention addresses itself to a practical problem well known in the art, namely the commutator sparking. The sparking being a persistent problem, it gives a characteristic disadvantage to any commutator machine. The invention presents a new and different means to improve the commutation properties of practical machines, thus competing with, or complementing the means known in the art (e.g., interpoles with commutating windings).
In order to understand the operation of the invention, there is no need to be concerned with all of the aspects of design and construction of electrical machines; therefore, unless specifically indicated to the contrary, such details as the number of poles, the particular type of winding employed (be it gramme, lap, wave, or yet another type useful in a commutator machine) will not be considered, following a long established practice in the art.